Allow TLD blocking using ABP style

This validates patterns without dots (only for abp style), allowing TLDs to be blocked

Signed-off-by: RD WebDesign <github@rdwebdesign.com.br>

gravity.sh

@@ -549,10 +549,12 @@ parseList() {
   # define valid domain patterns
   # no need to include uppercase letters, as we convert to lowercase in gravity_ParseFileIntoDomains() already
   # adapted from https://stackoverflow.com/a/30007882
-  # supported ABP style: ||subdomain.domain.tlp^
 
   valid_domain_pattern="([a-z0-9]([a-z0-9_-]{0,61}[a-z0-9]){0,1}\.)+[a-z0-9][a-z0-9-]{0,61}[a-z0-9]"
-  abp_domain_pattern="\|\|${valid_domain_pattern}\^"
+
+  # supported ABP style: ||subdomain.domain.tld^
+  # allow TLD blocking using ABP style: ||tld^
+  abp_domain_pattern="\|\|([a-z0-9]([a-z0-9_-]{0,61}[a-z0-9]){0,1}\.)*[a-z0-9][a-z0-9-]{0,61}[a-z0-9]\^"
 
   # A list of items of common local hostnames not to report as unusable
   # Some lists (i.e StevenBlack's) contain these as they are supposed to be used as HOST files